Problem in step 5

Hello I have a problem in step 5
When I measure with the red dots GND my reading is good 4.98, but
When I measure GND with green spots, do not mark anything
I can do?

Check it the LT1054 is inserted the right way (Notch/Dot to the right!)

4.97 reading is red
0.63 green

What are the voltages at pin 5 and 8 of the LT1054?

Black GND to pin 5 0.14
Black GND to pin 8 6.87
change the power adapter and 9 volt reading changes to Black GND to pin 8 8.23

So the LT1054 is not generating a negative voltage. Is the LT1054 inserted the right way? Are all the capacitors around it correctly soldered?

capacitors are good soldiers
and LT 1054 is positioned correctly
I can do

Check the LT1054 and the Eprom aren’t mixed up? :slight_smile:

Or the optoisolator?

I imagine (I can’t remember) that the guide and parts are nicely compartmentalised to stop people making the mistake, but things do happen.

with the Eprom, you mean the socket, which is housed lt 1054

Hello I have a problem in Step 5 When I measure with the red dots GND my reading is good 4.98, but when I measure GND with green spots is 0.63 reading

As I have said, there is a problem with the LT1054 or one of the parts around it. Please post of photo of the board, maybe we can spot the problem!

I agree to take a picture.
Should I buy a new 1054 Lt

Oh, it’s simpler than that… It looks like you have swapped the capacitors.

The 4.7uF capacitors are soldered in place of the 100uF capacitors.

capacitor C11 has changed the polarity
what you mean

You have not checked the value written on the capacitors!

You have soldered the 4.7uF capacitors in place of the 100uF capacitors.

You have soldered the 100uF capacitors in place of the 4.7uF capacitors.

The LT1054 needs a 100uF capacitor for C2. The capacitor you have soldered there is 4.7uF

now I just realized
sorry I’m a newbie

I just correct the mistakes and still giving the same readings.

have you checked the polarity of the tantalum cap? I’ve never done this mistake before - but maybe it could have damaged the LT1054 :confused: ?

as I check it?
I do not understand

There’s a little row of **+ on the positive side of it to mark the positive lead.